Welcome! It's always nice to get more people coming here. I have done some TASing of this game myself, but most of it was on VBA rather than BizHawk.
I want to give as much information I can. I know a few things about this game, and want to give you the best chance I can.
I'm not sure if it's the fault of my settings or whatever, but I'm getting a desync at the first hole when viewing your run. Anyway...
The introduction. You can save and quit the instant you gain control over your character. This lets you skip a bunch of dialogue. In addition, this might also be a good time to set fast text speed. Lastly, the golf tournaments are available from the main menu, rather than having to walk there yourself.
You can clear the game any% just fine with Singles alone. If your goal is to get to some sort of ending, this would likely be acceptable.
Luck manipulation: Wind, rain, and shot variance depends on RNG. As you should be getting Eagles or better, there will be confetti in the animation. This confetti has the power to call winds and summon rainstorms, by delaying some frames at that screen. If you need to tweak the wind, that would be the way to do it.
A list of luck manipulation methods I know of:
* Delay at confetti screen
* Delay during rain
* Switch to Green close-up view
* Delay long enough to hear a chirping bird
If your goal is speed, you'll want to get to your next shot as quickly as possible. If your ball is traveling slowly, it's spending those seconds being slow rather than dealing with your next shot. And if you can reach the hole with the next shot without that extra distance of a Topspin, it might be a good idea to use a Backspin instead.
Don't be afraid of rough terrain. In fact, if you can still reach the hole from there, going into a Rough is actually an advantage. With reduced maximum power, you can confirm your shot sooner. Additionally, rough terrain lowers the height of your next shot, meaning the ball spends less time in the air.
I'll have to find some of my things. I do have a fun side TAS (.vbm, for VBA, not BizHawk)
where I make a variety of shots in a contest. Once I'm better organized, I'll track down some of my older things and let you take a look at those.
I'll be giving my support in hopes you can create a good TAS.
I am aware of one speedrun you can watch, if you need ideas.
EDIT: Oh, this guy beat his older run I linked up there.